Optical zoom uses adjustments in the camera lens like a magnifyng glass so that the full resolution of the camera sensor is covered by an enlarged scene (zoomed in, higher zoom level) or shrunk scene (zoomed out, lower zoom level). Digital zoom takes a "crop" of the avilable sensor image and expands it's pixel count, typically to a 4k (12MP) frame. At increasing zoom levels this is like looking through a pinhole that has a decreasing size at greater zoom levels. I did some rectangle math and estimate that my phone, the S25 Ultra 12MP Super Telephoto at maximum zoom is effectively equivalent to a frame from a 1.2MP camera magnified by 33 times. In comparison with my 30MP mirrorless, interchangeable lens camera, using a 1600mm lens I get 32x magnification but the image size stays at 30MP and it was visible in image from each. I estimated my 30MP mirrorless with a 32x lens viewing a scene 4 miles away had twenty five times as much detail as my Galaxy S25U 12MP Super-Telephoto at maximum "zoom" of the same scene each taken a few minutes apart using a tripod for the phone and camera. Using zoom beyond the optical range of the camera has to reduce the real resolution of the final image. The S24 and S25 have some features to "enhance" such images but I rarely find them productive.
I typically choose which camera to use, mostly use the 200MP (Wide-angle) like a standard lens on a SLR camera for near subjects and almost always only use 1x zoom on the W camera (move myself to make a better scene rather than use zoom because the subject is usually a few feet away), then use the 50MP (Telephoto) for distant scenes and almost only use zoom between 1x and 5x (the optical zoom range of the T camera). Even then I prefer the 50MP T camera at 1x zoom as much as I can. I sometimes use the 50MP Ultra-Wide) camera but only at 0.6x zoom, the only optical zoom it supports, it can be good for broad acenes like landscapes because it has an extremely wide field of view. I rarely use the 12MP (Super Telephoto) camera, the optical zoom range is only 1x to 3x and it has a quarter the resolution of the 50MP T so even though the ST camera has a longer focal length I find that for most uses within the optical zoom ranges the 50MP T produces higher resolution frames than the 12MP ST camera.
If I can't make the scene perfect within the optical zoom range or by re-composing (moving myself), I take the best frame I can on the highest resolution camera suitable for the scene and crop my final image using a different app from the camera (Photos, Lightroom, etc) which starts with the higher resolution frames I get when staying within the optical zoom range. The result is typically higher resolution final images than I get by using the digital zoom (i.e. zoom beyond the lens optical zoom range).
I believe the S24 cameras are the same as the S25 but I haven't actually checked recently. The 200MP also has optical image stabilization that can reduce blur from shake when handholding the phone. It's the camera I use for close subject at 1x zoom only and using my legs instead of zoom to compose. Image stabilization can cause problems with some types of subject but that's rare and image stabilization is generally helpful.
There are several ways one phone could have better images at maximum zoom than the other, I'd have to see the image in each case to comment. I will say that reducing the amount of "automatic adjustment/enhancement" applied by the camera often results in better quality images. Those settings are found in various places, including the camera app, which mode is used in the camera app and also in the phone settings app.
For the record, these points shouldn't be considered "rules" or the "best practive" for using the phone cameras. Every scene is different and you are the artist for your pictures.
